An encoding method which allows reduction in the amount of codes is provided. The encoding method includes: setting step S11 for setting a quantization matrix set; quantization step S12 for performing quantization on a target block using the selected quantization matrix; and encoding step S13 for encoding, in a mutually associated manner, the target block which has been subjected to the quantization and identification information for identifying the quantization matrix set which has been set. In setting step S11, a quantization matrix set selected from a plurality of quantization matrix sets is set as the quantization matrix set to be used to perform the quantization on the target block, the plurality of quantization matrix sets including a custom quantization matrix set which is arbitrarily specified and a plurality of defined quantization matrix sets which have been respectively defined in advance.